One of the things that I've been working on is improving the composition of my photos. Many photographers would swear that the best way to practice and improve is to shoot with a prime lens as this forces you to think more about the placement of subjects in your viewfinder. The lack of any zoom capability means that you will be forced to use your feet: Subject too far away? Step forwards. Subject too near? Step backwards. The general idea is that when you start moving on your like this, you're also going to be bound to try out different angles and what not.

Another aspect that I wanted in a lens was a huge aperture. I wanted good low light performance, without having to bump the ISO up to 1600 or more. A side effect of the wide aperture would be some very shallow DoF in photos that (to me, at least) adds a very "nice" touch since it becomes a lot easier to isolate your subject from the background.

I'd originally considered a Sony 50mm f1.4 lens or even a Minolta 50mm f1.7, but these I found were a little too long. I needed something wider that would also serve as a general purpose lens. While Nikon have a 35mm f1.8 lens and Canon have a 28mm f1.8 lens (which a very good value!) Sony users have to rely on Sigma. This is one of my pet annoyances with Sony, but let's not get into that

I've had the Sigma 30mm f1.4 for over 2 months now and have taken about 4000 photos with it. I was in Beijing in April 2009, and this lens was the primary lens used in that trip. Hopefully, this should mean that I have a slightly better insight into this lens having actually used it extensively and not just taken some test photos in a shop, or some test charts.

The Sigma 30mm f1.4 carries the EX label and thus is coated in the "crinkle" finish that Sigma are tremendously fond off. It feels weird, and some people don't like it while others don't mind it. Some have described it as feeling like shark skin... The lens mount is metal and it uses internal focusing so the front lens element does not rotate. This makes the lens very useful for polarizers and more importantly ND grad filters. The focus ring is nicely placed at the front of the lens with distance markings clearly labeled. It rotates counter clockwise to get to infinity, thus is consistent with the other Sony lenses that I've owned.

All the lenses I've had either extend when zooming or when focusing. This Sigma maintains a constant length throughout and the lack of moving parts makes the lens feel a lot more solid.

To sum up, I can't find any fault in the build quality of this lens.

This lens weighs about 400 grams and balances really well on my Sony A200. The lens mount fits tightly and the whole package feels secure and inspires confidence. This sense of confidence can be slightly misguided, particularly if you read the section on focusing.

Focusing

The lens uses a HSM on Canon and Nikon mounts, but for some stupid reason Sigma have decided to eschew all that on the Sony. The Sony version of this lens uses the camera's built-in focusing motor. As such I think focus isn't as fast or as quiet as it could be. It's a real pity that Sigma still insist on charging Sony customers the same price as they do Canon and Nikon users, so keep this in mind when buying this lens. If you're using anything other than Canon/Nikon, check to see if it supports HSM or if it'll use some other focusing method in order to avoid potential disappointment.

From my experience, this lens requires a fairly contrasty subject in order to focus correctly. This is no problem in daylight and the lens focuses correctly with little problem. There is one condition where it fails, and I'll mention that later. In low light conditions this lens can find it difficult to lock onto a target. This makes it a little bit of a bummer, since that nifty f1.4 appears to be wasted if this lens doesn't focus in low light! The annoying thing is that it doesn't do this consistently(!!). A rough guess would be 4 out of 5 shots will focus correctly and this gets rather annoying since you can't be sure that you've nailed the focus until you check the LCD screen later. This could be down to the camera (bottom of the range Sony A200) and I will try to go to a shop at some point and try out other cameras.

There's also an issue with focusing at infinity. This seems to be a fairly common problem and it appears to be fairly random. A lens that misfocuses at infinity on one camera will happily focus correctly when attached to a different camera. See Ken Rockwell's article on this for pictures of the effect. His Nikon D200 focuses too near when going to infinity, while my A200 mostly goes to greater than infinity (just slighly but it's noticeable when you use anything less than f/4). I say mostly, because some shots (maybe 1 in 20) it will nail the focus correctly (!!!!).

While this lack of focusing consistency can be annoying, in practice this is no big deal. The problem becomes unnoticeable at f/4 and most of my landscape shots are done in f/8. If you're planning on doing nighttime landscapes, you can always manual focus it to infinity and then you'll get crisp images.

This problem does really annoy me though, so if you're a Canon/Nikon user I would suggest buying your manufacturer's equivalent to this lens.

Sample shots

Louise in a Beijing Cafe. f1.4.

Louise at the Temple of Heaven. f1.4.

The two photos above show what this lens is truly capable of. I love the photos taken at f1.4 and I love the background blur.

f8, ISO 100.

f1.4, ISO 320.

Summary and conclusion

This is a fairly decent lens when it's working correctly. I think part of the issues is down to the camera and another part of it is due to Sigma's implementation of AF algorithms. I've heard rumours that the reason Sigma's perform so poorly in AF on Sony bodies is because they've had to reverse engineer the algorithms. Don't know if that's true but I've owned 4 Sigma lenses now and 2 of them have had focus issues. One of them (my Sigma 28-70 f2. was so obviously backfocusing at f2.8 but the people at Sigma said it was fine and performing to spec. -.-

Keep in mind that the current list price for this lens is £460 in the UK. I think that's way over priced and I wouldn't pay more than £200 for it (I paid £260 as I bought it before the price hike). If you can get over the focus issues or if you're lucky enough to get a copy that focus correctly with your camera, you'll enjoy yourself tremendously. If you're unlucky like me, you'll still enjoy yourself but then feel like something's missing....

Thanks for the review. The issues are particularly interesting as I feel a lot of it could also be applied to the 10-20. In a quick scan of my fave shops it looks like best street price is lower £3xx but typically closer to £400 which is a bit much for what we get especially with the lack of HSM.

Having said all that, there isn't any other "affordable" choice. The nearest Sony 35mm f/1.4 G is over double the price.